We believe, therefore, that the study practices and patients were reasonably representative of northeast Scotland.
In other areas, local factors could affect the performance of replicated clinics.
We found that the most influential confounding variable was baseline performance: if this was already high then patients had less to gain.
Baseline United Kingdom data on secondary prevention, however, were reported in the ASPIRE study and presented a similar suboptimal picture to the baseline position in northeast Scotland.
In an attempt to assess the importance of baseline performance at the general practice level, we divided study practices into quartiles.
Patients were found to benefit in all groups of practices, although most improvement probably occurred in those with the lowest starting point.
It seems likely, therefore, that the results of this study will be relevant to other areas.